timerEvent firing creates extra JoinInstance on a persistent process

Attached project with JUnit test to see it:

• A persistent process with two live activities, a workItem and a timerEvent (see attached image
• The workItem fires, and one side of the execution waits in a safe state in the AND join.
• When the timer events, the TimerNodeInstance is notified, but it creates another JoinInstance instead of using the existing one.
• Since it is an AND join, it never continues because one JoinInstance has one incoming connection satisfied, and the other JoinInstance has the other.

If this is due to writing my BPMN2 wrong or a configuration, please let me know. I'm pretty sure the process should be valid as is.